1. Technical Field
The invention relates to telescoping rods, particularly to ratchet type telescoping rods.
2. Related Art
A cargo bar is a telescoping rod used in pickup truck beds or sport utility vehicles for holding cargo therein. Typical cargo bars adopt a unidirectional ratchet mechanism such as U.S. Pat. No. 5,979,876. Briefly, '876 is composed of a toothed rod and a ratchet actuator. There are a series of slant teeth 14 on one side of the toothed rod 10. The toothed rod 10 passes through the ratchet actuator. The ratchet actuator includes a wrench bar 22, a main pawl 26 and an auxiliary pawl 32, all of which are separately pivotally linked in a carriage 16. The two pawls 26, 22 are separately articulated to the wrench bar 22 with two shafts 28, and engage with two different teeth 14. An elastic member 40 is disposed between the two pawls 26, 32. An outer end of the wrench bar 22 is disposed with a handle 24. When the handle 24 is reciprocated, the wrench bar 22 drives the pawls 26, 32 to push the teeth 14 on the toothed rod 10, and then the toothed rod 10 is elongated outwards.
A single reciprocation cycle of the wrench bar can only elongate the toothed rod by the length of one tooth. It is so hard to elongate a much longer distance. Thus a quick release mechanism for making the toothed rod freely movable by temporarily withdrawing the pawls from the toothed rod is required. In '876, however, the quick release mechanism is a quick release lever 48 pivotally linked in the wrench bar 22 by a shaft 50 and near the handle 24. And a torsion spring 56 is put axially around the shaft 50. Two ends of the torsion spring 56 bear against an outer end 54 of the quick release lever 48 and the wrench bar 22, respectively. An inner end 52 of the quick release lever 48 bears against the elastic member 40. When the quick release lever 48 is depressed, the inner end 52 will push the elastic member 40 to move the auxiliary pawl 32 upwards and then to withdraw from the teeth 14. At this time, the toothed rod 10 can be freely moved.
Such a quick release mechanism is complicated in structure because it requires two elements—quick release lever 48 and torsion spring 56.
Furthermore, its assembling process is also laborsome. Thus it is uneconomical for manufactures. On the other hand, because the quick release lever 48 must has a specific length for serving as a lever, it tends to be fractured or bent. Thus it is not durable enough for users.